As the power of computer host systems increases, the required converted power of a power supply for supplying electric power increases accordingly, and the technical issues of increasing the converted power reside on a heat dissipating structure. Particularly, a 1U power supply is limited by the height as specified by the universal standard 1U specification and installed to a fan having a height less than 40 mm, and thus the wind or airflow provided by the fan is very limited. Obviously, the design of heat dissipating holes at an air outlet or an air inlet for guiding heat dissipated airflow becomes a key point of the design. In FIG. 1, present designs generally build heat dissipating holes on a rear panel of the power supply, but such arrangement cannot meet the requirements of a power supply with a large power. Some designs also build heat dissipating holes on the four walls at the rear of a power supply, but the heights of the power supply and the computer host system is equal, such that when the power supply is installed in the computer host system, the heat dissipating holes on the upper wall and the lower wall are blocked by the upper casing and chassis of the computer host system, and the heat dissipated airflow cannot be guided, and the heat dissipating holes on the two walls are blocked by side panels of the computer host system or an installed electronic device such as a hard disk, and the heat dissipated airflow cannot be guided either.
In R.O.C. Pat. No. M255,639, the patent did not disclose whether or not the patented invention can be applied to the 1U power supply, but such invention must sacrifice a portion of the space inside the power supply to install a blower fan for a larger wind flow. In addition to an increased length of the power supply, the heat dissipating holes on the front panel cannot manage to guide and discharge the airflow, but the heat dissipated airflow will flow back at an electric power panel. To improve the backflow problem, both U.S. Pat. No. 6,520,851 and R.O.C. Pat. No. M306,684 disclosed related backflow prevention designs, but these patented technologies still cannot overcome the height issue of the 1U specification, and thus are not applicable for the 1U power supply.
U.S. Pat. No. 5,260,851 disclosed a power supply that is installed in a hard disk. Although an upper wall of the power supply constitutes a hard disk containing space by a height difference, the height difference cannot form an airflow passage effectively, and such patented invention cannot be applied in the 1U power supply.